Guest Mysticle31 Posted July 30, 2004 Share Posted July 30, 2004 Well I just came out of a VW Jetta vr6 converion. Great fun car! Looking for my next project. Thinking about a V8Z with suspension..the works In my experence, I've learned that lowering macpherson strut cars are BAD!! Becouse the roll center falls FASTER then the center of gravity, actually causing more of a tendency to lean (even with fermer springs then stock) The way to fix is to get REALLY stiff springs and those you woudn't want to run on the street. Macphersons really arn't the best anyhow, about average eh? So, I'm wondering if people on this board agreee with me or think I'm crazy. What suspension options are there for a Z to bloody HANDLE! Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 30, 2004 Share Posted July 30, 2004 Yep. You really don't want Zs too low. You can move the front control arm pivots up to counteract the roll center problem and/or use bumpsteer spacers, and you can section the struts so that you don't lose as much travel by lowering the car. Also by installing camber plates you get rid of the tall rubber insulators that are on top of the springs, which lowers the car a bunch with no ill effects other than a harsher ride. It is possible to lower a Z a significant amount using a combination of these things without having any negative effects. Without any of these things, if you lower the car more than about 2" you're asking for trouble. Here's some links to get you started on the suspension stuff: http://www.betamotorsports.com http://www.modern-motorsports.com http://www.arizonazcar.com http://www.motorsportauto.com Use the search function. If you have a question about bumpsteer or camber or caster, whatever, it's probably been dealt with before. Happy searching! Jon Quote Link to comment Share on other sites More sharing options...
260DET Posted July 30, 2004 Share Posted July 30, 2004 The all round strut suspension on the Z is one of its strongpoints it seems to me. The single greatest problem with the Z is the flexy body, the more rigid the chassis (body) the better the stock type suspension will work. Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 30, 2004 Share Posted July 30, 2004 It is amazing the difference in Z cars with the same suspenion, and a stiff chassis and a non-stiffened chassis. As with any car, the stiffer the chassis, the more predictable the handling. WIth the stiff chassis you also go from dealing with a 3 degree of freedom system (think of the actual suspension consisting of 3 springs, the tire, the spring, and the chassis) to a 2 degree of freedom system. (this time tire + spring) I honestly have no hard data on what the torsional rigidity of the Z chassis is, I haven't measured it. (I should sometime!) I would expect it would be much less than 1500ft/lbs per deg though in stock form. (A well sorted chassis should be pushing 3000ft/lbs per degree or more) Has anyone actually measured this on the Z? As far as spring rates go, you should be able to drop the Z 2" with minor ill effects, and less ill effects if you section the struts. I am running moderate spring rates (still streetable) and have a minimal amount of body roll. Quote Link to comment Share on other sites More sharing options...
Guest Mysticle31 Posted July 30, 2004 Share Posted July 30, 2004 Thank you for the links and info. So what is a good Z to start with? 240, 260, 280? A stiff chassis is required, but could I make a 240, 260 stiffer then the 280 without the weight vs 280 having all this weight and need to stiffin that up! These Zs are great! you can put V8s in em and have great weight dist, rear wheel drive, suspension stuff isn't very expencive (compared to other cars I've dealt with.) Braking is WOW expensive. For the most part becouse (I think) you get new aluminum stuff. Are there any bolt ons from other cars? I like just alittle to much for the street. Just a little to much power, suspension, brakes.. (more twared race) I've noticed that you have to choose the spring rates for some of the suspension kits. Where can I find proven nice firm examples of spring rates? (make sure the res. frequency is good, balence is good..) Swaybars? (My Jetta had 300lb fronts and 200lb rears on a 2200lb car. that firm or fimer would be awsome!) Quote Link to comment Share on other sites More sharing options...
zguy95135 Posted July 30, 2004 Share Posted July 30, 2004 It depends, 280's are easier to find and are a lot cheaper. Its not too hard to lighten the 280's, the huge bumpers weight a bunch (about 150lbs) so does the stock AC, header, put on lighter wheels (even stock alloys) ect. Plus they already have a stiffer chassis over the 240. On the other hand 240's are rarer and more expensive, but are more flexy. BTW check out this awesome 8 point front brace, wish I had $250 I could spare http://www.pdkfabrication.bravepages.com/240%20front.htm Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 30, 2004 Share Posted July 30, 2004 The 240z can be made stiffer than the 280z for the same weight. However, the 280z is stiffer to begin with. I've noticed that you have to choose the spring rates for some of the suspension kits. Where can I find proven nice firm examples of spring rates? (make sure the res. frequency is good, balence is good..) Swaybars? (My Jetta had 300lb fronts and 200lb rears on a 2200lb car. that firm or fimer would be awsome!) Looking in the areas of 200lb/in to 250lb/in is good for a dual duty street/autocross setup. It's pretty stiff on the street in the Z, but works well. Search this site and you'll come up with lots of discussion on coilover springs, rates, lengths, etc. Quote Link to comment Share on other sites More sharing options...
Guest Mysticle31 Posted July 30, 2004 Share Posted July 30, 2004 Heres a Q.. What do I have to do with a Z to get 50/50 weight dist with a V8? Do I have to use a LS1 (All aluminum, therefore light!), I can't obviously use all cast iron? What about cast iron with aluminum heads/rad..etc? I've read about JTR kits and some book that you buy for info?? Quote Link to comment Share on other sites More sharing options...
Mike kZ Posted July 30, 2004 Share Posted July 30, 2004 Heres a Q.. What do I have to do with a Z to get 50/50 weight dist with a V8? Do I have to use a LS1 (All aluminum' date=' therefore light!), I can't obviously use all cast iron? What about cast iron with aluminum heads/rad..etc? I've read about JTR kits and some book that you buy for info??[/quote'] Go to http://www.jagsthatrun.com and buy the Datsun manual. Whith a cast block, aluminum heads, and the block sitting as far back towards the firewall plus lower in the engine compartment, it will give you that 50/50 weight. Quote Link to comment Share on other sites More sharing options...
Guest Mysticle31 Posted July 30, 2004 Share Posted July 30, 2004 So where can I find kits that get the engine far back as possible? I'd imagine if I used LS1 with the same factors, I'd have more rearword weight dist? Does the cast block add weight to the car? (Johns, said that the Z with a V8 weights 2700lbs with ZX are fatter!?) Quote Link to comment Share on other sites More sharing options...
Drax240z Posted July 30, 2004 Share Posted July 30, 2004 All you questions have been answered dozens of times, do a search and do some reading. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted July 30, 2004 Share Posted July 30, 2004 Check my new sig!!! Quote Link to comment Share on other sites More sharing options...
Guest Mysticle31 Posted July 31, 2004 Share Posted July 31, 2004 Thank you much.. I've been doing some reading. And I've come to several conclusions at the moment (I'll be doing more reading) 300HP seems to be the limit before you have to do extensive body strenghening Also seems to be the limit if you treat a T5 tranny well It would be nice if it would get you in the low 12's mabey just on a good day in your dreams tuch in the high 11s. Do you need to swap diffs for 300HP? Did they make any LSD's that were not R200? It would be nice to come up with enought rearword squat on launch to make the best use of traction but still have NICE FIRM Controlled FIRM!! suspension for road race use. Is that possible? Is nose dive good for braking? Like rear squat is good for launching? but side to side movement is bad for cornering? Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.